2 



gallon of foreign alcohol. By a special indulgence of the Commissioners of Customs, to whom 

 the difficulty had been submitted, the dutiable spirit was permitted to be destroyed in the 

 presence of an Officer of the Customs Department at Barrow, and on receipt of his certificate 

 that this had been done, the duty charge was refunded. The material in each bottle was put 

 into a fine silk sieve and the foreign spirit allowed to drain away without loss or injury to 

 the collection. The material was then replaced in the bottle and 70°/ o British Methylated spirit added. 



From a series of collections taken in an area like that investigated by the 'Siboga' in 

 1899 — 1900, especially as the Hensen vertical net had been employed to some extent to obtain 

 the deep water plankton, one could almost expect results rather above the ordinary. The 

 collection has decidedly proved most interesting and instructive. Much valuable information 

 relating to the distribution of knovvn species of Copepoda has been gained from the investigation 

 of the material. Some of the species described by former investigators that had become almost 

 lost owing to incomplete description and illustration, have been re-discovered and are now 

 placed on a more satisfactory basis. 



The Copepoda noted in this report reach the total of 338 species, and of this number 

 83 do not appear to have previously been described. This collection has produced a greater 

 number of species from a definite tropical area than has been secured in modern times, and 

 distinctly proves the importance of a lengthened systematic collection in securing reliable results. 

 The following table shews the results of comparatively recent investigations of the Copepoda 

 in definite tropical areas, compared with what was revealed by the voyage of the 'Challenger' 

 1873—1876. 



'Challenger' Copepoda 107 species. 



Gulf of Guinea Copepoda (10 weeks collections) 150 species. 



') Ceylon Copepoda (about 6 months investigation) 234 species. 



Maldive Area Copepoda 120 species. 



'Siboga' Copepoda (exclusive of Asterocheridae and true parasitic forms). 338 species. 



Much of the increase in the number of species is without any doubt largely due to the 

 greatly improved facilities for collecting and investigating material, of course every expedition 

 now organised has all the previous experience of the others as a guide, and the specialist is 

 provided with a good supply of literature. At the beginning of the 'Challenger' expedition 

 many methods had never been tested, or even suggested, and the literature was very scanty. 



A good deal of investigation has already been done amongst the Copepoda of the 

 Indian Ocean, and a fair amount of information is available relating to the Copepoda of even 

 the Malay Archipelago. 



If we compare the families represented in this report with the same families already 

 recorded from the Indian Ocean, we find the following particulars: — The late Professor Cleve 



1) This number includes the seven species of Copepod Fish-Parasites recorded by C. B. Wn.sox in Supplementary Report 

 XXXIV, Part V (1906), Report on the Pearl Oyster Fisheries of the Gulf Manaar. The Supplementary Report VII by THOMPSON .V SCOTT 

 (1903) deals with a total of 284 species representing various families, but 57 of these species were obtained from plankton collected during 

 the traverse to and from Ceylon and were not actually present in the Gulf of Manaar. The last day of the outward journey, and the 

 first day of the homeward one only, is regarded as part of Ceylon in the above list. 



